It tends to behave poorly when there's a word it doesn't recognize (like "doll'd"—I hope to add support for more of these poetic spellings just as I added support for spelling words like "dancing" as "dancin'"), so that might be partly at play with some of what you're seeing. But I think there's also something else going on here—it previously didn't ever generate so many consecutive syllables with the same stress, so I probably introduced a regression at some point. I'll investigate and add more tests for that too!
Lastly, a byproduct of my own background and the corpuses I use is that this does work better with "modern" poetry. For example, Shakespeare's Sonnet 29 starts with this line:
> When, in disgrace with fortune and men’s eyes
In the intended iambic pentameter, it would be:
> when, IN disGRACE with FORtune AND men's EYES
I don't know enough history to know if people ever spoke English like that, but that interpretation is way off to a modern reader. If I didn't know it was supposed to be iambic and was trying to diagram the stresses, I'd do something like:
> WHEN, in disGRACE with FORtune and MEN'S EYES
Meter is hard!
I'm very new to English poetry, I might be entirely wrong here. But when I input some famous poems, the way this app puts stresses is quite a bit different from my understanding.
For instance, for
> Bards of Passion and of Mirth,
It sees _and_ as unstressed, the second _of_ as stressed, and _Mirth_ as unstressed, which doesn't quite make sense to me to be honest.
> Tomorrow and tomorrow and tomorrow
It sees both _and_ as unstressed, while my understanding is that this verse is better read as fully iambic, putting stresses on both _and_.
> And what is love? It is a doll dress'd up / For idleness to cosset, nurse and dandle
https://i.imgur.com/raPMDnc.png
It sees four consecutive unstressed syllables. I'm not sure what is the logic here.